The Pentagon’s decision to add new F-15EXs to its budget request for the Air Force, a move not requested by the service itself, was based on a lack of capability and capacity of the current fleet and the presumptive cheaper cost of the Eagles, the military’s top uniformed officer told lawmakers on Thursday.

The Pentagon’s fiscal 2020 budget request includes about $1 billion for eight F-15EX “advanced Eagles,” a decision that stemmed from former Defense Secretary Jim Mattis.

Chairman of the Joint Chiefs of Staff Gen. Joseph Dunford told the Senate Armed Services Committee the “framework” of the decision came from a study of the future needs of the military’s tactical aircraft fleet, which showed the Air Force had a shortage in its number of aircraft and the amount of ordnance those aircraft could carry.

"Then they had the F-15C, which was aging out in the 2027-2028 period," he said "So, within the next five or 10 years the best solution was to go to the F-15, called the EX, platform to backfill the F-15. Eventually we’ll get to an all F-35 program, but from both a cost perspective and a capability perspective, this particular mix of aircraft for the near term was determined to be the right mix of aircraft.” (end of excerpt)